The technology is related to Voice over Internet Protocol (VOIP) telephone systems which connect telephone calls to or from devices using data packet communications. In a typical VOIP system, users can place and receive telephone calls using IP based telephones, computers running IP telephony software, or via a normal analog telephone which is connected to the Internet via a telephone adapter. In each of these instances, the device which sends and receives data packets over a network has a device identification number. The device identification number is used by the VOIP telephony service to help route calls to the appropriate devices.
For example, assume that a customer of a VOIP telephony service utilizes an IP telephone to place and receive telephone calls. When another party calls the customer's telephone number, the call is initially routed to the VOIP telephony service provider. The VOIP telephony service uses the dialed telephone number to determine the identification number of the customer's IP telephone. The VOIP telephony service provider then connects the call to that IP telephone.
In such a system, each customer's telephone number is typically associated with the identification number of only a single IP telephony device. In some instances, a single telephone number may be associated with multiple IP telephony devices. However, each of those IP telephony devices would be associated with a single customer or user account. In other words, there is a one-to-one correspondence between telephone numbers and users/accounts.
In those instances where a customer has multiple IP telephony devices associated with a single telephone number, when a call is received for that customer, the VOIP telephony service might ring all of the customer's telephony devices at the same time, and then connect the call to whichever device answers first. Alternatively, the VOIP telephony service might ring one of the customer's telephony devices first, based on call handling instructions. If the first device does not answer the call, the VOIP telephony service might then ring the second device.